Protein and carbohydrates mobilization rate and their relationship with grain yield in simple hybrids of white and yellow maize

Carbohydrates and proteins are the major components of corn grain. These macromolecules are mobilized from the leaves to grain in order to obtain a favorable yield. An important step in validation of maize hybrids is the metabolic performance that allows to increase grain quality. The present study intended to evaluate the metabolic performance of simple corn hybrids based on protein and carbohydrates content, its mobilization rate and its relationship with grain yield, during flowering and grain maturation. Leaf total soluble protein (TSP) and total carbohydrate (TCB) accumulation were quantified; protein (PMR) and carbohydrate (CBMR) mobilization rates were estimated, and crop yield was measured. Three simple white grain (GB5, GB4, GB3) and three yellow grain (GA4, GA5, GA1) maize hybrids, obtained through a cross in a diallelic scheme in Celaya, Guanajuato, Mexico, were used. A significant variability in TSP and TCB content was observed among the established hybrids. All hybrids showed TSP concentrations between 30–45 mg g⁻¹ DW⁻¹ during flowering and 2–10 mg g⁻¹ DW⁻¹ during grain maturation. TCB content in all hybrids was higher than 55 mg g⁻¹ DW⁻¹, independent of the time of evaluation (flowering or grain ripening). The mobilization rates were higher than 70% in both white and yellow grain hybrids, but there was intra-hybrid variability. GB5 hybrid showed highest correlation of TSP and TCB, and PMR was higher than CBMR. In GB hybrids, TSP correlated with yield more than TCB. The hybrids with best response of the evaluated variables were GB5 and GA4.